Disclosed are apparatus and methodology for reducing humidity (i.e., moisture) and/or heat within and/or adjacent a patient support mattress, without requiring any electrical power. A spacer fabric is used to create a non-crushable area of support below a patient's core area, where moisture and heat more commonly buildup. Integrated air cells in the mattress have resilient elements such as open-celled foam interiors. The air cells are connected by air tubing to the spacer fabric, and the mattress is otherwise vented externally from the spacer fabric. As a result, the patient's movement causes air to be expelled from or drawn into the air cells, which in turn results in air movement in the spacer fabric below a patient or user, resulting in cooling effects by removing moisture and/or heat, all without requiring external or internal electrical power.